Resistance welding apparatus



March 21, 1950 E. M. LAUGHNER RESISTANCE WELDING APPARATUS Filed July26, 1947 a M Z a f a l M Q A A L A A ///VYA INVENTOR Er'n 232 MLaugh/1e).

AT RNEY mwz 91/- W Patented Mar. 21, 1950 UNITED STATES PATENT OFFICE.

RESISTANCE WELDING APPARATUS Ernest M. Laughner, Jeannette, Pa.,assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., acorporation of Pennsylvania Application July 26, 1947, Serial No.763,785

2 Claims.

- l My invention relates, generally, to resistance welding apparatuaandit has reference in particular to resistance welding electrodes and electrode holders for use in resistance welding machines.

;.Generally stated, it is an object of my invention to provide animproved holder for spot welding electrode tips which is simple andinexpensive to manufacture, and which is both easy to use and reliablein operation.

More specifically, it is an object of my invention to provide a spotwelding electrode holder, of the fluid-cooled ejector type, having aflexible seal between the body of the holder and the ejector mechanism.

Another object of my invention is to provide forusing a flexible bellowsmember to seal the ejector mechanism in an electrode holder.

' Yet another object of my invention is to provide :tor using a flexiblemetal bellows member I for positively sealing a movable knockout ram tothe body of an electrode holder.

' It is also an object of my invention to provide, in aresistancewelding electrode holder, a unitary knockout ram and fluid pressureseal.

A 'further object of my invention is to provide for eliminating theusual source of leaks which occur in spot welding electrode holders ofthe ejector type.

' It is an important :object of my invention to provide, in a spotwelding electrode holder, for using amovable water tube as a striker forejecting an electrode tip from the holder.

Other objects will, in part, be obvious and will, ln-part, be explainedhereinafter.

In practicing my invention in one of its forms, the body of an electrodeholder comprises a cylinder having a tapered bore at one end forreceiving a spot welding electrode tip. Inlet and outlet connections fora cooling ,fluid are provided through the wall of the cylinderconnecting with the bore, and a water tube is positioned in the bore toprovide a defined path of flow for the Jfluid between the inlet andoutlet connections. The water tube is movable longitudinally of the borefor engaging the inner end of the electrode tip. A knockout ram ismounted on the end of the body remote from the electrode tip by means ofa flexible metal bellows member, which provides a positive fluid sealand permits movement I of the ram to actuate the water tube for ejectingthe electrode tip.

For a more complete understanding of the nature and scope of myinvention, reference may be made to the following detailed description 2which may be read in connection with the accompanying drawing, in whichthe single figure is an elevational View in section of a resistancewelding electrode showing an electrode holder embodying the invention inone of its forms.

Referring to the drawing, the reference numeral Ill may denote,generally, a resistance welding electrode which may be used with eitherarm of a resistance welding machine. In this instance it is shown asclamped between the jaws II and I2 of the lower arm of a resistancewelding machine by clamping means such as the bolt It, for performing awelding operation in connection with the electrode tip I5 of anelectrode which may be similarly secured in the upper arm (not shown) ofthe welding machine.

The electrode Ill may comprise ,a holder I6 having a substantiallycylindrical body member or barrel I! with a central longitudinal bore l8therethrough. The bore may be provided with a tapered surface .20 at theupper end for receiving an electrode tip 2! having a complementarytapered surface and provided with a longitudinal recess 22 open at thelower end for receiving a cooling fluid. Transverse openings 24 and 25may be rovided through the body member I! into the central bore It forreceiving inlet and outlet conduit connections 21 and 28 for supplying asuitable cooling fluid to the electrode tip 2|. A boss 29 having athreaded shoulder 30 maybe attached to the lower end of the body memberll for securing a fluid under pressure seal to seal the lower end of thebore 3, as will be described more in detail hereinafter.

In'order to provide for removing or ejecting the electrode tip 2| fromthe body member I! of the holder 1 6, an ejector mechanism may beprovided comprising, for example, an elongated ejector or striker .3!which may be movably positioned within the bore l8 so as to project fromthe lower .end of the body member. The upper end of the striker .3! maybe positioned adjacent the inner end of the electrode tip 2,! so astoengage it when actuated for ejecting the electrode tip from the bodymember. The lower end of the striker may be provided with an enlargedhead portion 32 having a shoulder 33 for engaging the boss 29 to limittravel of the striker.

In order to provide for directing the flow of a cooling fluid from theinlet connection 21 to the electrode tip 2|, the striker 3| may beutilized as a water tube and provided with a longitudinal bore 35 in theupper portion having a. transverse opening 36 normally positioned inalignment with the inlet opening 24. Passage for a cooling fluid betweenthe inlet opening 24 and the opening 36 into the central bore of thestriker may be assured, either by providing a peripheral groove aboutthe striker 3| in alignment with the inlet opening 24, or by utilizing aset screw 31 in the body member IT for engaging an elongated axial slot38 in the striker to maintain the opening 36 in alignment with the inletopening 24, as shown. An adjustable water tube 39 may be positioned inthe central bore 35 of the striker adjacent the upper end so as toproject upwardly into the longitudinal recess 22 of the electrode tip 2|for directing the cooling fluid immediately adjacent the working surfaceof the electrode tip. A return passage 40 for the cooling fluid to theoutlet opening 25 may be provided by either making the upper portion ofthe striker 32 of reduced cross-section, as shown, or by utilizing asuitable length of tubing of less diameter than the body of the strikerand suitably secured thereto, whereby an annular passage is providedconnecting the recess 22 with the outlet opening 25.

For the purpose of sealing the lower end of the bore l8 to preventleakage of the cooling fluid therefrom, flexible fluid sealing meansdesignated, generally, by the numeral 44 may be utilized. The sealingmeans may comprise a nut 45 having a central aperture 46 providing asliding fit with the lower end of the striker 3|, and which is screwedonto the boss 29. A knockout ram 41' may be positioned adjacent thelower end of the striker 3| and disposed to be struck a sharp blow foractuating the striker to remove the electrode tip 2 l. to the nut 45 bymeans of a flexible sealing member such as a diaphragm, or the bellowsmember 48 which may be soldered, brazed, welded or otherwise secured tothe nut and ram. The ram and striker may comprise separate elements asshown, or they may be made integral if desired.

In operation, cooling fluid enters through the inlet conduit 2'! andpasses through the side opening 36 into the central bore 35 of thestriker 3|. It then passes through the water tube 39, is directedagainst the inner end of the recess 22 in the electrode tip 2| andreturns by way of the peripheral passage 40 to the outlet conduit 28.

The metal bellows 48 provides a positive seal against leakage of thecooling fluid from the lower end of the holder It. If it is desired toremove the tip 2| to dress it or replace it, the ram 41 may be struck asharp blow with a hammer. The striker 3| is actuated thereby to engagethe lower end of the tip 2| and eject it from the bore l8. The bellowsmember 48 permits movement 01' the ram and striker while maintaining apositive fluid seal.

' From the above description and the accompanying drawing, it will beapparent that I have provided an improved resistance welding electrodeholder which is simple and inexpensive to manufacture and which is easyto use and to maintain. By utilizing a metal bellows member,

The knockout ram 41 may be connected or the like, for sealing theejector mechanism, no leaks will result due to wear oi. the movablestriker as a result of use. The flexible seal provided in accordancewith my invention is permanent and requires no continued adjustments tomaintain the seal leakproof. Since the water seal and the knockout rammay comprise a unitary assembly, replacements may be easily andinexpensively made.

Since certain changes may be made in the above-described constructionand different embodiments of the invention may be made, withoutdeparting from the spirit or scope of the invention, it is intended thatall the matter contained in the above description and shown in theaccompanying drawing shall be considered as illustrative and not in alimiting sense.

I claim as my invention:

1. In an electrode tip holder, an elongated conductive body memberhaving a longitudinal bore with a tapered seat at one end to receive aremovable electrode tip, conduit means providing inlet and outletconnections with the bore for a. cooling fluid, a striker movablydisposed in the bore, said striker having an opening therethrough at oneend communicating with one of the conduit means to direct the coolingfluid and projecting from the body member at the other end. a ramdisposed to engage the projecting end of the striker, and a singleresilient metal bellows member connecting the ram to the body member.

2. An electrode comprising, an elongated conductive body member having alongitudinal bore with. a tapered portion at one end and a threadedshoulder at the other end, conduit means providing inlet and outletconnections for passing a fluid through the bore, an electrode tipseated in the tapered portion of the bore and having a recess in itsinner end, a water tube including a onepiece striker member movablypositioned in the bore to engage the inner end of the electrode andprojecting from the other end of the body member, said striker memberhaving an axial bore opening at the end adjacent the electrode andconnecting with one of the conduit means, and a resilient sealconsisting of a single metal bellows member having a ram at one end toengage the projecting end of the striker and a threaded bushing at theother end disposed to engage the threaded shoulder of the body member.

ERNEST M. LAUGHNER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,385,108 Seelofi Sept. 18, 1945FOREIGN PATENTS Number Country Date 567,387 Great Britain Feb. 12, 1945

